I think the thing they need to consider most is what will the people buying the toys recognise the most? If all they've known is the film, then the more likeness the better I'd wager.
However, I'm sure there's a middle ground to be had somewhere though in terms of likeness rather than just sculpting the actors. They are toys after all.
Although after spending most of my childhood with model paints trying to make my He-man figures look like the cartoon, one thing I regret is never being able to get a movie He-man! Maybe this will be my chance!